1. Field of the Invention
The present invention relates to a linear solenoid.
2. Description of Related Art
JP-A-2005-45217 describes a linear solenoid that drives a switch valve to switch an oil passage. The linear solenoid has a shaft to press and drive a spool of the switch valve in an axis direction. As shown in FIG. 13 of JP-A-2005-45217, an end portion of the shaft opposite from the spool is slidably supported by an inner wall of a cylindrical part of a rear stator, and the shaft has reciprocation movement together with a movable member. The cylindrical part has an opening opposite from the movable member, and the opening opens to outside of the linear solenoid. In this case, the rear stator is easily produced by pressing operation. However, if operating oil flows from the switch valve, the oil may leak out of the linear solenoid through the opening of the cylindrical part. Therefore, a location of the linear solenoid is limited to inside of an engine when the linear solenoid is used for driving a switch valve of a valve timing controlling device.
As shown in FIG. 2 of JP-A-2005-45217, an end face of a linear solenoid adjacent to a rear stator is molded with resin. In this case, the linear solenoid can be arranged outside of an engine, because operating oil never flows out of the linear solenoid, due to the molded resin. The rear stator has a based double cylinder shape. Therefore, resin can be prevented from flowing into the linear solenoid when the end face of the linear solenoid is molded with resin. However, the rear stator having the based double cylinder shape is difficult to produce by pressing operation. For example, cutting and shaving process is necessary for producing the rear stator. In this case, producing cost of the linear solenoid is increased.